Electric carburetor



Aug. 16, 1966 M. A. KNIGHT ELECTRIC CARBURETOR Filed Dec. 30, 1964 INVENTOR MILTON A. KNIGHT (M MW Wit/'TORNEY 7 AGENT United States i atent 3,266,783 ELECTREC CARBURETUR Milton A. Knight, Rte. 1, Box 113, Centreville, Va. Filed Dec. 30, 1964-, Ser. No. 422,464 4 Claims. (Cl. 2611) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalities thereon or therefore.

This invention relates to carburetors for gasoline engines and more particularly to carburetors which utilize the interaction of electromagnetic and electrostatic forces to control the rate of fuel flow into the engine.

In the conventional type of carburetor, the rate of fluel flow into the engine is controlled entirely by mechanical means. When the engine is running, a partial vacuum is created in the intake manifold. The pressure differential which exists between the intake manifold and the atmosphere causes air to flow through the carburetor into the intake manifold and engine cylinders. As the air passes through a venturi in the carburetor, its velocity is increased and its pressure decreased. This reduced pressure in the venturi zone acts to draw fuel from the carburetor fuel bowl into the carburetor throat through a nozzle located in or near the venturi. The quantity of fuel-air mixture which is permitted to flow into the engine is controlled by a throttle or butterfly type of valve which is placed in the carburetor at a point downstream from the fuel nozzle and venturi. The fuel-air ratio is controlled by means of a choke, a second butterfly type of valve which is located in the carburetor throat upstream from the venturi and fuel nozzle. By decreasing the quantity of air permitted to flow past the choke, the fuelair ratio may be selectively increased.

The liquid fuel which enters the venturi zone from the fuel nozzle is vaporized by the low pressure existing in that zone. The vaporization of the fuel may be enhanced by means of heat risers near the downstream portion of the carburetor, which conduct a portion of the exhaust gases into close proximity with the fuel charge, thereby utilizing the heat of the exhaust to increase the vaporization of the fuel. However, since engine efficiency is strongly affected -by the uniformity of fuel distribution throughout the charge, and by the degree of vaporization of the liquid fuel droplets, effort is continually being directed toward improving these characteristics.

Additional mechanical control means are ordinarily provided for adjusting the fuel-air ratio in response to changing conditions of engine temperature and desired power setting.

As is well known in the art, an increase in engine load causes the speed of the engine to drop. With the reduced speed of the engine, the manifold pressure increases, thereby reducing the pressure differential which produces the fuel flow, resulting in a decreased rate of fuel flow into the engine. If it is desired to maintain a constant engine speed, it becomes necessary for the throttle opening to be increased so as to permit a greater quantity of fuel to flow into the engine. Conversely, when the load on the engine decreases, the engine speed tends to increase, resulting in a drop in manifold pressure and a tendency for fuel flow to increase. It therefore becomes necessary to reduce the throttle opening in order to maintain a constant engine speed.

It is the primary purpose of this invention to provide means for more completely vaporizing the liquid fuel which enters the carburetor, so as to provide more com- 'ice plete combustion of the fuel and thereby increase the efliciency of the engine.

It is a further object of this invention to provide means for more uniformly distributing the fuel charge throughout the air stream.

It is another object of this invention to provide means for automatically adjusting the rate of fuel flow int-o the engine in response to changing engine load conditions.

Other objects, advantages and novel features of the invention will become apparet from the following detailed description of the invention when considered in conjunction with the accompanying drawing wherein the figure is a cross-sectional view of the carburetor embodying this invention.

When an electrostatic charge is placed upon small liquid droplets, the droplets disintegrate into submicron size. Because of the electric field space charge effects, the charged particles will tend to repel each other and disperse themselves evenly in a volume of gas. In this condition, if the charged particles are then subjected to an electric or electromagnetic field, their motion will be influenced by the direction of the resultant field force. Because of the relatively low mobility or high inertia of the liquid fuel particles, they will tend to propel the surrounding gas, which has relatively high mobility and low inertia, in the same direction. The unique electric carburetor of this invention utilizes the above principles to improve both the distribution and the vaporization of the liquid fuel.

Referring now to the figure, carburetor 10 is mounted on the engine intake manifold 11. Fuel is supplied to carburetor 10 from carburetor fuel bowl 12 by means of fuel nozzle 13. Carburetor 10 consists of three separate tubular sections. Air enters at the upstream section 14 and flows sequentially through sections 15 and 16 to the intake manifold 11. The middle section 15 is fabricated from an electrically non-conductive material, while section 16 is fabricated from a metallic electrically conductive material. Venturi ring 17 is located in the insulated portion 15 of the carburetor and is made of a metallic electrically conductive material. Fuel nozzle 13, also electrically conductive, is placed slightly upstream from venturi ring 17 so that the fuel droplets which emerge from the nozzle will be immediately subjected to the reduced pressure zone within the venturi.

A source of DC. potential 21 is connected to fuel nozzle 13 and to venturi ring 17 so that each of these latter two elements will function as an electrode. D.C. source 21 is also connected to section 16 of the carburetor.

A second source of DC. potential 22 is connected in series with a variable resistor 23 and a multi-turn coil 24 which surrounds section 15 of the carburetor for a purpose hereinafter to be described.

A third source of DC. potential 25 is connected in series with a pressure-sensitive variable resistor 26. This circuit is connected to coil 24 in a parallel relationship to the circuit which includes battery 22 and resistor 23. The pressure-sensitive element of resistor 26 communicates with intake manifold 11 by means of a conduit 27. An adjustment screw 28 is provided on resistor 26 for the purpose of permitting selection of an initial setting of the resistance value of resistor 26.

The operation of this unique carburetor will now be described. As occurs in a conventional carburetor, the running engine creates a reduced pressure in the intake manifold 11, which acts to draw fuel from the fuel bowl 12 into the carburetor via fuel nozzle 13. As the fuel droplets emerging from nozzle 13 enter the reduced pressure zone within venturi 17, they are vaporized. DC. potential source 21 provides a voltage of 1,000 to 3,000 volts across the gap between nozzle 13 and venturi 17. The desired magnitude of this voltage is dependent upon the spacing between the nozzle and venturi ring. The voltage magnitude is further selected to provide adequate fuel charging, but must remain well below the breakdown strength of the fuel-air mixture so as to'elirninate any danger of arcing. The fuel particles in the zone between nozzle 13 and the venturi 17 are immediately charged, and are thereby further disintegrated into subinicron size. Gasoline, having very low surface tension, is particularly susceptible to this action. These charged fuel particles, all having the same charge polarity, tend to repel each other and distribute themselves evenly and uniformly throughout the flow through the carburetor.

The current flowing through coil 24 creates an electromagnetic field inside carburetor 10, and the charged fuel particles passing through this zone are subjected to an electromagnetic force. Because of the inter-action of the electrostatic and electromagnetic forces on the charged particles with the electromagnetic force resulting from coil 24, the charged fuel particles will follow a spiral path down the carburetor. Since this path is nonparallel to the axis of the carburetor, a component of the resulting force will always be available to act along the axis of the carburetor for the purpose of either accelerating or retarding the flow of fuel particles as desired. Since section 16 of the carburetor is maintained at the same potential as fuel nozzle 13 by means of DO. source 21, there will be no tendency for the fuel particles traveling through the carburetor to be attracted to the side Walls of this section.

It is contemplated that the desired direction of the resultant force acting upon the charged fuel particles would be reverse to the direction of flow of the particles. This is thought to be necessary since the throttling effect of the conventional butterfly valve does not exist in this electric carburetor, and it would therefore be necessary to provide other means for resisting the downstream-directed force acting on the fuel resulting from the pressure differential between the intake manifold and the atmosphere. If it should be thought desirable to supercharge the engine, this result could be accomplished by reversing the direction of fiow of current through coil 24, thereby reversing the direction of the result-ant force acting upon the fuel. The magnitude of the force generated by coil 24 may be manually controlled by means of variable resistor 23. If it is desired to provide an accelerating force as well as a retarding force, means could be provided for reversing the polarity of the current through coil 24. By mechanically connecting resistor 23 to a conventional throttle control linkage, the rate of fuel flow can be readily controlled by thus varying the current flow through coil 24.

Pressure-sensitive resistor 26 may be of the carbon pile type. Pressure from the intake manifold 11 is applied to the car-hon pile by means of a bellows.

The circuit which includes resistor 26 functions to automatically adjust the quantity of fuel-air mixture entering theengine in response to changes in the engine load conditions. As was discussed previously, an increase in engine load causes a drop in engine speed, which in turn results in an increase in the manifold pressure. This increase in manifold pressure reduces the pressure differential between the manifold and the atmosphere, and thereby reduces the flow rate of the fuel-air mixture. The reduced fuel flow has the effect of further reducing the engine speed. Since it is ordinarily desirable to maintain or even increase engine speed during an increase in load, it becomes necessary to increase the rate of fuel flow. The novel electric carburetor of this invention automatically makes this adjustment. If, as is contemplated, it is desirable to normally retard the fuel flow with the electromagnetic force of coil 24, it is necessary to decrease the current flow through coil 24 so as to reduce the retarding force, in order to increase the fuel flow. Thus, resistor 26 would be arranged so as to increase the resistance when manifold pressure rises. In this way, the fuel flow rate can be automatically increased. Conversely, to de-- crease the fuel flow when the engine load is decreased, the resistance value of resistor 26 would be decreased.

The principal advantage provided by this unique electric carburetor is the improved efficiency of fuel utilization. This improved efliciency results from the fact that the fuel droplets entering the carburetor throat are immediately broken down into an extremely fine vapor. This assures more complete combustion of the fuel. Furthermore, the fact that the fuel particles are all charged with a like polarity improves the fuel distribution throughout the air fuel mixture. Each of these effects contributes to greater efficiency in the utilization of fuel entering the cylinders. A further advantage which results from the use of this novel carburetor is the automatic compensation of fuel flow in response to changing engine load conditions, thus eliminating the need for a manual adjustment of the fuel flow setting.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A carburetor for as park-ignition engine, having an intake manifold, comprising:

conduit means connected to the engine intake manifold for directing a mixture of air and fuel into the engine;

fuel inlet nozzle means in said conduit means and electrically insulated therefrom;

circuit means for providing a direct current potential between said nozzle means and said conduit means; control means for providing a variable strength electromagnetic field in said conduit means;

whereby said circuit means places an electrostatic charge on the fuel entering said conduit means, and the resulting interaction of the charged fuel and the electromagnetic field creates a force, the magnitude of which may be varied by said control means, there- 'by to regulate the rate of fuel flow into the engine.

2. A carburetor for creating an air-fuel mixture; and controlling the admission thereof'to a gasoline engine intake manifold comprising:

conduit means having a downstream end connected to the engine intake manifold, an upstream end substantially open to the atmosphere to permit the entrance thereto of air, and a central electrically nonconductive portion;

electrically conductive venturi ring means concentrically disposed inside the central portion of said conduit means;

fuel line means providing a flow path for liquid fuel entering the carburetor, said fuel line means terminating in a nozzle portion disposed within the central portion of said conduit means and adjacent the upstream side of said venturi means;

circuit means for providing a direct current potential between said nozzle portion and said venturi ring means; and

control means for providing a variable strength electromagnetic field in said conduit means;

whereby the potential created by said circuit means places an electrostatic charge on the atomized fuel droplets which exit from said nozzle portion, the flow rate of the charged fuel droplets being thereafter regulated by said control means.

3. The carburetor of claim 2 wherein said control means comprises:

an electrical coil surrounding said conduit means; and

a manually operable variable resistor operatively con- References Cited by the Examiner {15:21:31 ggflsaid coil for varying a current supplied UNITED STATES PATENTS 4. The carburetor of claim 3 wherein said control means 2,645,279 7/ 1953 Rossnian 15836.3

further comprises: 5 3,110,294 11/ 1963 Nyman.

a pressure-sensitive variable resistor having a pressure 3,116,726 1/1964 Kwartz.

responsive element connected by means of a conduit to the engine intake manifold; FOREIGN PATENTS means for supplying a current to said pressure-sensitive 814 269 6/1959 Great Britain variable resistor, said pressure-sensitive variable re- 10 sistor being operatively connected to said coil. HARRY B. THORNTON, Primary Examiner. 

1. A CARBURETOR FOR AS PARK-IGNITION ENGINE, HAVING AN INTAKE MANIFOLD, COMPRISING: CONDUIT MEANS CONNECTED TO THE ENGINE INTAKE MANIFOLD FOR DIRECTING A MIXTURE OF AIR AND FUEL INTO THE ENGINE; FUEL INLET NOZZLE MEANS IN SAID CONDUIT MEANS AND ELECTRICALLY INSULATED THEREFROM; CIRCUIT MEANS FOR PROVIDING A DIRECT CURRENT POTENTIAL BETWEEN SAID NOZZLE MEANS AND SAID CONDUIT MEANS; CONTROL MEANS FOR PROVIDING A VARIABLE STRENGTH ELECTROMAGNETIC FIELD IN SAID CONDUIT MEANS; WHEREBY SAID CIRCUIT MEANS PLACES AN ELECTROSTATIC CHARGE ON THE FUEL ENTERING SAID CONDUIT MEANS, AND THE RESULTING INTERACTION OF THE CHARGED FUEL AND THE ELECTROMAGNETIC FIELD CREATES A FORCE, THE MAGNITUDE OF WHICH MAY BE VARIED BY SAID CONTROL MEANS, THEREBY TO REGULATE THE RATE OF FUEL FLOW INTO THE ENGINE. 